Compound for electric devices

ABSTRACT

A method providing for the reduction of noise originating from core-and-coil elements of electrical devices by encasing the core-and-coil elements within a chemical compound combination comprising at least two organic compounds, the combination having large d-loss factor values at starting and stabilization temperatures, respectively, of the core-and-coil elements. A typical mixture comprises an unsaturated polyester and a polyurethane.

United States Patent Ayano et al.

COMPOUND FOR ELECTRIC DEVICES Inventors: Hiroyoshi Ayano; YasuakiKibino; Hiroyoshi Sato; Yukihiko Ohta; Minoru Fukuhara, all of 1048 OazaKakoma, Kadoma-shi, Osaka, Japan Filed: Aug. 6, 1970 Appl. No.: 61,776

Related US. Application Data Continuation-in-part of Ser. No. March 29,1967, abandoned.

Foreign Application Priority Data April 4, 1966 Japan ..41/21071 Oct. 7,1966 Japan ...41/65655 Oct. 11, 1966 Japan ...41/67353 Oct. 17, 1966Japan ...41/67821 Oct. 17, 1966 Japan ...41/67822 Nov. 9, 1966 Japan..41/73729 US. Cl. ..336/96, 260/28, 260/37,

Int. Cl ..HOlf 15/02 Field of Search ..336/96, 100, 205; 264/272; 174/52PE, DIG. 2; 26 0/28, 37 N, 858

References Cited UNITED STATES PATENTS 9/1968 Holzinger ..336/96 Aug. 8,1972 2,464,568 3/1949 Flynn et al ..336/96 3,235,825 2/1966 Davis, Jr..336/96 x 2,414,525 1/1947 Hiyl et al. ..336/96 3,488,616 1/1970 Duncanet a1. ..336/96 3,319,203 5/1967 Haughney ..336/96 2,788,499 4/1957Pappas ....336/96 x 3,102,246 8/1963 Honey et al. ..336/100 1,769,9067/1930 Cameron ..336/96 2,484,215 10/1949 FQStCl' ..336/96 3,163,83812/1964 Antalis e! 111.... ....336/96 x 3,211,695 10/1965 Peterson..336/96 x Primary Examiner-Thomas J. Kozma Att0rneyWolfe, Hubbard,Leydig, Voit & Osann, Ltd.

[57] ABSTRACT A method providing for the reduction of noise originatingfrom core-and-coil elements of electrical devices by encasing thecore-and-coil elements within a chemical compound combination comprisingat least two organic compounds, the combination having large d-lossfactor values at starting and stabilization temperatures, respectively,of the core-and-coil elements. A typical mixture comprises anunsaturated polyester and a polyurethane.

5 Claims, 22 Drawing Figures H Hg 2 Loss Factor Loss Factor 0 50 I00 o 05o |oo c Temperature Temperature F/g. 3 AQ 4 Z 5 LI E 0 50 I00 C 0 50[00 C Temperature Temperature Phone 5 Phone 6 20 2o L/ TO I Noise Name 050 I00 c 0 50 too Compound Temperature Compound Temperature [NVENTORSHuzovosm AYANO YASUAKI K/B/NO Hnzovosm SATO YUklHIKO OHTA MINORUFUKUHAQA a n/31, MM, 'I/aTd-GM ATTYS PATENTED M19 81972 SHEET 2 BF 5Phone 8 I6 |5- I I z I [0. g I 1 0'03 o'oe ooe Loss Factor Phone Hg. 7F/g. 9

20 Phone 10 I0 g i O 50 I00 C 0 50 I00 "C Compound Temperorure CompoundTemperature F/ /0 Phone 9 Phone 0) g IO 2 2 O 50 IOO C 0 50 I00 CCompound Temperofure Compound TemperoTure [.N'VENTORS HIROYOSHI AwwoYASUAKI memo Hmovosm SATo YUKIHIKO OHTA MINORU FUKUHARA 1: 1 /0470, MM,VJq-QMZMATTYS.

P'ATENTEDAUB 8 I912 SHEET 3 [IF 5 Phone Phone 5a 160 c CompoundTemperatu re 50 p0 Compound Temperafure O 50 I00 C Temperarure PhonePhone Y 0 5O 1 C Tem pera T u re [X I 'EXTORS O 50 I00 C Temperature omm 8 K rm w H mo MOM S KN R RU V HYHYW PATENTEDAus 8 I972 SHEET U BF 5F/ Phone 9 3O 3 Temperorure O 50 iOC c Temperofure INVENTORS HmovosmAYANO YAsuAKa Kasmo Hmovosm SATO YUKIHIKO OHTA MmoRu FUKUHARAPATENTED'Auc 8 I972 SHEET 5 BF 5 COMPOUND FOR ELECTRIC DEVICES Thisapplication is a continuationin-part of our copending application Ser.No. 626,751 filed Mar. 29, 1967, now abandoned.

INTRODUCTION This invention relates generally to the reduction of hum orother noises originating from magnetic actions occurring in thecore-and-coil elements of electrical devices. It particularly concernsthe reduction of such noises in the ballast elements of discharge lamps.

The term transformer hum" originated from noises emitted from thecore-and-coil elements of transformers or other electrical devicesalthough it is characteristic of all electrical devices whose mechanismsinclude in part, a core-and-coil element. Such undesirable noises resultfrom vibrational energy induced by electromagnetic forces inherent inthe core-and-coil elements.

Discharge lamps containing ballasts are typical examples of suchelectrical devices. A discharge lamp may generally be defined as a lampcontaining a low pressure gas or vapor which ionizes and emits lightwhen an electric discharge occurs. Fluorescent materials are sometimesused on the inside of the glass envelope to increase the illumination,as in an ordinary fluorescent lamp.

Discharge lamp ballasts mainly consist of a core-andcoil elementtypically comprising a coil of copper wire wound on a core of thin ironstampings. The two main functions of such ballasts are to give thehigh-voltage inductive kick necessary to start the lamp when the currentpassing through the lamp is interrupted, and to maintain the currentthrough the lamp within the proper range once the lamp is started.Ballasts are designed for the particular wattage and voltage of the lampin which they are to be used.

Noise or transformer hum from such ballasts is caused by vibration dueto the magnetic action in the ballast core-and-coil element and isaggravated when the vibrations are transmitted to the supporting frameof the metallic panel. Noise is generally generated by magnetostrictivechanges in the dimensions of the core, by vibration of the core, and bystray magnetic fields causing vibration of the ballast case or even ofthe fitting in which the ballast is mounted.

When discharge lamp fixtures are used in factories,

large stores and other places where a fairly high noise levelcontinuously exists, the noises produced by their ballasts are not ofprimary importance. However, when discharge lamps are installed in quietlocations, such as hospitals, libraries, offices and living rooms, evenslight noises can be bothersome and annoying. Solutions for reducingsuch noises are constantly being sought. One suggested solution hascalled for a more efiicient mounting of the ballast on soft rubber orplacing some similar non-rigid material between the ballast and themetallic mounting. While some of the noise can be eliminated by propermounting, the noise level emitted still remains objectionable for manypurposes.

Another solution has called for encasing the ballast within a resinouscompound. However this solution reduces noise only in certain limitedtemperature intervals within the operating temperature range of theballast. Typically, the operating temperature range of a ballast willvary from about C. to about 130 C.

Within this temperature range it is typical to find ballast startingtemperatures of about 0 C. to about 30 C. and stabilization temperaturesof about to about 1 30 C.

The auditory sense is very conscious of noise emitted when a lamp isfirst turned on due to the abrupt interruption in the relativelynoise-free environment. The auditory sense also becomes very sensitiveto noise emitted by discharge lamps after their stabilization due toannoyingly continuous repetitious sound. The time period between suchstarting and stabilization temperatures is very short. Therefore, anynoise existing therebetween is of little significance in terms of anuisance value. Consequently while all of the listed proposed solutionsare somewhat effective, ballast noise annoyingly remains.

It is therefore an object of this invention to provide an electricaldevice containing a core-and-coil element which is substantially free oftransformer hum or other noises derived from the magnetic action ofcoreand-coil elements.

In one of its specific applications, it is an object of this inventionto provide a discharge lamp fixture which is substantially free fromballast noise.

With more particularity, it is also an object of this invention tosubstantially reduce ballast noise associated with discharge lampsduring that period of time when it is most annoying to auditorysensitivity, i.e., upon starting the discharge lamp and after thedischarge lamp has stabilized.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings in which:

FIG. 1 is a graph showing loss factor as a function of compoundtemperature for illustrative thermoplastic and therrnosetting resins.

FIG. 2 is a graph showing loss factor as a function of compoundtemperature for an illustrative organic mixture typical of thisinvention.

FIG. 3 is a graph showing loss factor as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester resin and a polyurethane.

FIG. 4 is a graph showing loss factor as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and an asphalt.

FIG. 5 is a graph showing noise level as a function of compoundtemperature for a polyurethane.

FIG. 6 is a graph showing noise level as a function of compoundtemperature for pitch.

FIG. 7 is a graph showing noise level as a function of compoundtemperature for an unsaturated polyester resin.

FIG. 8 is a graph showing the relationship between noise and the d lossfactor.

FIG. 9 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a polyurethane.

FIG. 10 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a blown asphalt.

FIG. 11 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a polyurethane.

FIG. 12 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a polyurethane.

FIG. 13 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a polyurethane.

FIG. 14 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a polyurethane.

' FIG. 15 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a blown asphalt.

FIG. 16 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a straight asphalt.

FIG. 17 is a graph showing noise level as a function of compoundtemperature for an organic compound combination comprising anunsaturated polyester and gilsonite.

FIG. 18 is a graph showing noise level as a function of compoundtemperature for an organic combination comprising an unsaturatedpolyester and a blown asphalt.

FIG. 19 is a graph showing noise level as a function of compoundtemperature for an unsaturated polyester.

FIG. 20 is a perspective view of a contained coreand-coil element beingcharged with a resinous mixture.

FIG. 21 shows a cross sectional view of an electrical device containinga core-and-coil element, charged with a uniform resinous mixture.

FIG. 22 is a perspective view of a dissassembled electrical devicecontaining a core-and-coil element encased within separately moldedresinous plates.

While the invention will be described in connection with a preferredembodiment, it will be understood that we do not intend to limit theinvention to that embodiment. On the contrary, we intend to cover allaltematives, modifications and equivalents as may be included within thespirit and scope of the invention.

As noted above the prior art has shown the use of single resinouscompounds to encase ballast core-and-coil elements in order to reducenoise. However, as further indicated above such a use was far from beingtotally effective in reducing noise. Noise reduction took place onlywithin certain temperature intervals of the ballast operatingtemperature range which varies from about 0 C. to about 130 C.Furthermore, adding to the total ineffectiveness in using these singleresinous compounds is the sometimes low degree of sound reduction in thetemperature interval where noise is reduced. Consequently, noise may bereduced at either starting temperatures of about 0 C. to about C. or atstabilization temperatures of about 70 C. to about 130 C. and even then,such reduction may be ineffective due to its low degree. However,effective noise reduction at starting and stabilization temperaturesdoes not take place. This is a definite shortcoming since it is at thesetemperatures that noise is most bothersome as noted above.

We have discovered the reason for this partial and sometimes ineffectivenoise reduction. The reason may be explained by first referring to FIG.1 which shows d loss factor values which will be defined below for twodifferent organic compounds as a function of temperature. Curve Aassociated with a thermoplastic resin shows a maximum d loss factorvalue at about 20 C. and Curve B associated with a therrnosetting resinshows a high d loss factor value at about 130 C. It has been discoveredthat d loss factor values for a given organic compound may be employedas a measure of the conversion ratio of vibrational energy to heatenergy. Therefore, as d increases a larger proportionate amount ofvibrational energy is dissipated in the form of heat energy andconsequently a smaller amount of vibrational energy is transmittedthrough the organic compound. While the use of the therrnosettingcompound as an encasing compound will reduce noise at stabilizationtemperatures of about 70-130 C. due to its high d loss factor values atsuch temperatures, it will not eflectively reduce noise at startingtemperatures of about 030 C. due to its low d loss factor values at suchtemperatures; and consequently there will be a small conversion ofvibrational energy to heat energy at such starting temperatures.Similarly, while the thermoplastic compound will reduce noise atstarting temperatures of about 0-30 C., it will not effectively reducenoise at stabilization temperatures of about 70-130 C, due to its low dloss factor value at the stabilization temperatures. Consequently,neither compound will effectivelyreduce noises at both starting and'stabilization temperatures. Furthermore, if the magnitude of the d lossfactor values is too low there will be a low degree of conversion ofvibrational energy to heat energy.

The prior art in failing to appreciate the correlation between d lossfactor values and noise reductions is not aware of the limiting effectof d loss factor values in using only one encasing organic compound andthe degree of sound reduction as affected by d loss factor values.

In order to illustrate the effect of using single compounds in reducingnoise of a sequence ballast for two 40 watt fluorescent lamps, threeballasts for such fluorescent lamps were charged with polyurethane,pitch, and unsaturated polyester, respectively. The polyurethane resinwas mixed with quartz sand. The d loss factor values for polyurethane,pitch, and an unsaturated polyester at 0 C., room temperature, and C.are given in Table I.

TABLE I d loss factor values Organic Compounds 0C Room Temp. 100Cpolyurethane 0.13 0.10 0.05 pitch 0.08 0.10 0.05 unsaturated polyester0.04 0.06 0.07

resin After the ballasts had been charged with these organic compounds,noises emitted therefrom were measured as a function of organic compoundtemperature with a precision noise meter, placed 2 meters from theballast. The results are given in FIGS. 5, 6, and 7, respectively. FIG.5 shows that noise reduction was initially efiective at startingtemperatures but as the temperature of the compound rose, noisesincreased. FIG. 6 shows efiective noise reduction at startingtemperatures but as the compound temperatures increased, so did noise.FIG. 7 shows effective noise reduction at stabilization temperatures buthigh noise levels at starting temperatures.

Noise versus temperature relationships for FIGS. 5, 6, and 7 attemperatures of 0 C., room temperature and 100 C. are given below inTable II.

TABLE II Noise level in phons Organic Compound 0C Room Temp. 100Cpolyurethane 8 l0 1 9 pitch 12 16 unsaturated polyester 1 8 l 6 l 2 Incomparing Tables I and II it is noted that large d loss factor valuesare related to more effective noise reduction.

In accordance with this invention, sound emission from core-and-coilelements of electrical devices is effectively reduced by disposing amaterial comprising the combination of first and second organic membersaround the core-and-coil element such that it is substantially encasedby the material. The first organic member must have a maximum d lossfactor value, preferably greater than about 0.06, over the temperaturerange of about 0 C. to about 130 C., in the starting temperatureinterval of the core-and-coil element. Similarly, the second organicmember must have a maximum d loss factor value, preferably greater than0.06, over the temperature range of about 0 C. to about 130 C., in thestabilized temperature interval of the core-and-coil element.Consequently, the material comprising the first and second organicmembers will have a maximum d loss factor value over the temperaturerange of about 0 C. to about 130 C. in the starting and stabilizationtemperature intervals. The overall effect produced by the preparedmaterial when it is applied as an encasing agent of core-and-coilelements is to effectively reduce noise over the temperature intervalswhere the human auditory sense is most perceptive.

As just noted the d loss factor values for the organic compoundsconstituting the organic compound combination are preferably greaterthan about 0.06. This value was arrived at by first determining thenoise level generated by the core-and-coil element of discharge lamps,which is annoying to the users of such lamps when installed in suchlocations as general ofiices, libraries and the like. The majority ofusers became particularly annoyed at noise levels of 16 phons or more.Being aware of this value experiments were conducted in which threedifferent organic compounds having known varying d loss factor valueswere respectively placed within the ballasts of three lighting fixtures,each having two 40-watt fluorescent lamps whose source voltages andfrequencies were 100 volts and 60 cps respectively. The noise levelsgenerated by each of the three lamps were plotted respectively againstthe corresponding d loss factor values associated with the organiccompound placed in the ballast of each lamp. The mean values for thesetests are given in FIG. 8 where it should be noted that d loss factorvalues necessary to effectively dampen noise levels to values below 16phons should be greater than about 0.06.

This invention stems in pan from the discovery that d loss factor valuesare a measure of the conversion of vibrational energy to heat energy. Atthis point in order to more clearly define the d loss factor value,reference is made to various well known stress-strain deformationequations. Generally, in the static deformation of an elastic materialwithin the elastic limit, the stress applied to the elastic material isproportional to the strain as given by:

wherein ais stress, 6 is strain and E is a modulus of elasticitygenerally referred to as Youngs Modulus. In kinetic deformation thestress varies periodically, usually with a sinusoidal alternation, at afrequency v in cycles/secs or w =21rv radians/secs. The strainalternates but is out of phase with the stress. The stress can bedecomposed vectorially into two components, one in phase with the strainand one out of phase with the strain. When these vectors are divided bythe strain, the modulus, given as E, is separated into an in (real) andout-of-phase (imaginary) component given by:

wherein j is the imaginary unit T and d referred to herein as the d lossfactor value is the tangent value of the phase angle 8 which is adimensionless parameter conveying no physical magnitude, but rather ameasure of the ratio of energy loss to energy stored in a cyclicformation. It has been discovered that this relationship can also bestated as a measure of the conversion ratio of the vibrational energy tothe heat energy.

The d loss factor value for a given compound may be determined byspecifically designed commercially available equipment. The basicapparatus used in determining the reported d loss factor values of thisinvention is identified as the Complex Modulus Apparatus 3930manufactured by Briiel and Kjaer of Naerum, Denmark. Instructions andbasic specifications for utilizing the Complex Modulus Apparatus inobtaining d loss factor values may be found in an operation manualpublished by the manufacturer entitled Instructions and Applications,Complex Modulus Apparatus Type 3930, dated 1964, the disclosures ofwhich are included herein by reference.

Referring to FIG. 2 there is shown the (1 loss factor value as functionof temperature for an organic mixture typical of that used in thisinvention. It should be noted that the organic compound combinationexhibits high d loss factor values at both starting and stabilizationtemperature intervals, i.e., at about 0l30 C. and l 30 C. respectively.With such a combination effective sound reduction will exist at bothstarting and stabilization temperatures of the core-and-coil elements ofelectrical devices.

In order to illustrate the effect of employing the organic mixture ofthis invention, as opposed to employing a single organic compound, theballast elements for each of five different two 40-watt fluorescentlamps measured at temperatures of C., 20 C., 60 C. and

l00 C. in the same manner described above. The results are given inTable III.

TABLE III Organic Sample Noise level in phons Compound No. 0C 20C 60Cl00C unsaturated l 15 l 1 l4 l2 polyester 2 l5 14 l 3 l 3 3 l3 7 8 l l 49 7 7 7 5 22 21 mean I5 I l l2 l3 urethane l 8 7 26 35 rubber 2 7 9 2637 3 6 9 27 37 4 6 6 30 37 5 7 7 28 37 mean 7 8 27 37 unsaturated 1 l0l2 l5 l l polyester plus 2 l3 l4 17 l l urethane 3 l l l0 l2 l0 rubber 47 9 9 6 5 7 7 7 9 mean l0 l0 l2 9 7 It can be seen from Table III thatthe noise level in the lamps using the combination of materials wasreduced throughout the temperature range 0 C. to 100 C., while the noiselevel in the lamps employing the individual organic compounds wasefiectively reduced only within those portions of the temperature rangeswhere they have sufficiently high d loss factor values.

Among the preferred organic compounds exhibiting high d loss factorvalues sufficient to effectively reduce core-and-coil noise atstabilization temperatures are unsaturated polyester resins, and mostpreferably those unsaturated polyester resins which have d loss factorvalues greater than about 0.06 at temperatures equivalent tostabilization temperatures of the coreand-coil elements they are toencase.

The preparation of unsaturated polyesters is generally well known in theart. They are typically prepared by reacting an unsaturated polybasicacid with a polyhydric alcohol. Unsaturated polybasic acids particularlysuitable in preparing the unsaturated polyester resins employed in thisinvention are maleic anhydride, adipic acid, succinic acid and phthalicacid. Particularly suitable polyhydric alcohols are ethylene glycol,diethylene glycol and propylene glycol. Once the polyester has beenformed, a vinyl monomer such as vinyl tolylene, divinyl benzene, orstyrene may be added as a cross linking agent and thereby copolymerizewith the unsaturated polyester.

In many instances it is necessary to solidify the unsaturated polyesterprior to its use. This may be accomplished by the addition of a settingcatalystto the unsaturated polyester. Such a catalyst may be, forexample, methyl ethyl ketone peroxide, benzoyl peroxide or a mixture ofone of the listed peroxide catalysts with either dimethyl aniline ordiethyl aniline.

' In order to illustrate the preparation of typical polyesters which maybe employed in the present invention, the following illustrativeexamples are given:

EXAMPLE A A reaction mixture comprising i.0 moles of maleic anhydride1.0 moles of phthalic anhydride and 2.2 moles of diethylene glycol wasreacted in carbonic acid gas flow at -l20 C. for 9 hours. An unsaturatedpolyester of oxidation No. 3.1 was obtained. Six hundred and thirtygrams of this unsaturated polyester were dissolved in 470 grams ofstyrene together with 150 milligrams of hydroquinone. A cross linkedunsaturated polyester was obtained.

EXAMPLE B A reaction mixture comprising 1.3 moles of maleic anhydric 0.7moles of adipic acid, and 2.2 moles of propylene glycol was reacted in acarbonic acid gas flow at l70220 C. for 8 hours. The mixture was furtherreacted for 1 hour at 220 C. under a reduced pressure of 150 mm. Hg. Anunsaturated polyester of oxidation No. 8.6 was obtained. This polyesterwas dissolved in styrene containing 220 ppm of hydroquinone. A crosslinked, unsaturated polyester containing 40 percent styrene wasobtained.

EXAMPLE C A reaction mixture comprising 1.0 moles of phthalic anhydride1.0 moles of adipic acid, 2.2 moles of diethylene glycol, and 2.2 molesof ethylene glycol was reacted in a carbonic acid gas flow at 160-205 C.for 7 hours. An unsaturated polyester resin having an oxidation No. of6.4 was obtained. The unsaturated polyester was cooled to 100 C.Subsequent to cooling, 1 mole of maleic anhydride and 170 milligrams ofhydroquinone were added. This mixture was reacted for 6 hours at atemperature of l220 C. and then for 1 hour at 220 C. under a reducedpressure of mm. Hg. The resulting unsaturated polyester had an oxidationNo. of 10.1. This polyester was then cooled to C. Styrene was addedthereto so as to produce a cross-linked unsaturated polyester resincontaining 40 percent styrene.

Among the preferred organic materials exhibiting high d loss factorvalues sufiicient to effectively reduce core-and-coil noise at startingtemperatures are polyurethane resins, asphalts, oils and fats. Mostpreferred are polyurethane resins, asphalts, oils and fats which have dloss factor values greater than about 0.06 at temperatures equivalent tothe starting temperatures of the core-and-coil elements they willencase.

The chemistry of polyurethanes, including their preparation, isgenerally well known as given in High Polymers Vol. XVI,PolyurethanezChemistry and Technology, Saunders and Frisch, IntersciencePublishers, 1963 which is included herein by reference. However, verybriefly stated, polyurethane resins typically used in preparing theorganic mixture of this invention may be produced by the reaction ofdi-or polyfunctional hydroxyl compounds with di-or polyfunctionalisocyanates. l-lydroxyl terminated polyesters of polyethers and morespecifically polyols such as castor oil, glycerine or pentaerythritolare some examples of the polyfunctional hydroxyl compounds. Theisocyanates normally used are the diisocyanates which are typicallymixtures of tolylene diisocyanate isomers. Cross-linked polymers havingrepeated urethane or urethane derived linkages may also be used. It maybe necessary to solidify the polyurethanes prior to their use, and thismay be accomplished by the addition of a setting catalyst to thepolyurethane. Typical examples of setting catalysts are N, N, N, N'-tetramethyl-l.3butanediamine and dimethyl ethanolamine.

Among the asphalts which exhibit high d loss factor values sufficient toreduce the noise of core-and-coil elements at starting temperatures arenatural blown asphalt, petroleum asphalt and gilsonite. Typical oils andfats which exhibit high d loss factor values sufficient to reduce thenoise of core-and-coil elements at starting temperatures are tung oil,linseed oil, cuttlefish oil, rape oil and the like. 7

The organic compound mixture or combination may be used in any of anumber of different physical forms. For example, it may vary from asubstantially homogeneous mixture of two organic compounds to atwo-plate assembly in a face-to-face relationship where the first platecomprises the organic compound having high d loss factor values atstarting temperatures and the second plate comprises the organiccompound having high d loss factor values at stabilization temperatures.

In a substantially homogeneous mixture, the proportionate amount of thefirst and second organic members will vary with the particular organicmixture being prepared. However, such proportionate amounts willnormally vary, on a 100 parts by weight basis, from about 25 to about 99parts, preferably about 50-90 parts, of organic compound having high dloss factor values at stabilization temperatures, and from about 1 I toabout 75 parts, preferably about 10-50 parts, of organic compound havinghigh d loss factor values at starting temperatures. For example theoptimum mixing ratio for unsaturated polyester resin and asphalt is 10to 99 parts by weight of the former to 30 parts by weight of the latter.

Inorganic fillers such as calcium carbonate, clay, quartz, sand, silicapowder or combinations thereof are preferably added to the organicmixtures of this invention in amounts equal to about 40 to about 80percent as based on the total weight of the organic members responsiblefor noise reduction. Such fillers to not influence the d loss factorvalues.

As an added safety feature provided to prevent electrical fires ignitedfrom the excessive heat generated by voltage overload, it is desirableto include an inorganic salt or salts having water of crystallization inthe organic combination. By using such inorganic salts the danger fromelectrical fires arising from voltage overload in the core-and-coilelement of an electrical device is greatly reduced. As the temperatureof the core-and-coil' element increases, the inorganic salt dischargesits water of crystallization in the form of water vapor; consequently,the probability of excessive heat generation is reduced due to theremoval of heat by the vaporization of the water of crystallization.However, it is necessary to select an inorganic salt whose water ofcrystallization will not discharge in the form of water vaporprematurely due to the heat generated during a setting reaction. If thewater of crystallization is removed prematurely, there will be noneremaining to remove dangerous heat build-up in the event of voltageoverload. Furthermore, excessive use of inorganic hydrated salts such aschloride salts may influence catalytic action and thereby adverselyaffect the setting of the organic compound(s). These salts arepreferably used in amounts of about 10 to about 40 percent by weight asbased on the total weight of the organic members responsible for noisereduction.

Some suitable inorganic salts having water of crystal lization are thefollowing:

Ca0 8H O discharging water of crystallization at C. SiO; 8H Odischarging water of crystallization at BaO 8H O discharging water ofcrystallization at SnCl 8H O discharging water of crystallization atBaCl 2H O discharging water of crystallization at CuSO, 3H O dischargingwater of crystallization at to C.

A1 0 31-1 0 discharging water of crystallization at If the mixture is tobe uniformly mixed, certain ingredient combinations require additionalpreparative steps. For example, it is difficult to uniformly disperseand mix asphalt with the other ingredients. Consequently, asphalt isfirst dissolved in a part or all of the monomer solvent of theunsaturated polyester resin. The asphalt-monomer solution is then mixedwith the remainder of the ingredients so that a uniform organic mixtureis produced.

In preparing the organic mixtures of this invention care must be takento always check the d loss factor value after its preparation. It hasbeen discovered that the final organic mixture does not necessarilycumulatively inherit the d loss factor values of the individual organiccompounds constituting the mixture.

The mixtures of this invention may be easily added to a case containinga core-and-coil element. FIG. 20 shows a transformer 3 and a condenser 4contained within a case 2 covered with a lid 1 being encased within anorganic mixture 5 of this invention by pouring the mixture 5 from amixture tank 6 into the case 2. The organic mixture 5 is shown as beingpoured in a dry state. When the mixture 5 is added in the dry state theingredients must be carefully chosen to ensure mixture fluidity. Forexample the use of excessive amounts of silica will reduce fluidity aswill certain organic compounds such as epoxy urethane rubber. However,the mixture 5 may be added to the case 2 in a wet state if the settingcatalysts are added to the mixture while it is in the case 2; thisprocedure insures that'the organic mixture will completely fill all thevoid space within the case 2 and removes mixture fluidityconsiderations.

FIG. 21 illustrates the completed electrical transformer assemblyprepared by the process illustrated in FIG. 20, including a transformercore-and-coil element 3 which is completely encased within the organicmixture 5 of this invention.

As previously noted, the organic compound mixture of this invention mayalso take the form of a two-plate assembly. Wherein the materialcomprising the combination of the first and second organic members is inthe form of plate assemblies comprising at least two plates in aface-to-face relationship. The first plate comprises the first organicmember defined above; the second plate comprises the second organicmember also defined above. The plate assemblies are disposed around thecore-and-coil element of said electric device by placing at least one ofthem along each side of the core-and-coil element. FIG. 22 shows sixplate assemblies 8, 9, 10, ll, 12 and 13 each being made up of a pair ofseparate plates 6 and 7 in face-to-face relationship. The plates 6 and 7may be either separable or permanently attached to one another. Plate 6comprises an organic material possessing a high d loss factor value atstarting temperatures, while plate 7 comprises an organic materialpossessing a high d loss factor value at stabilization temperatures. Thesix plate assemblies 8, 9, 10, 11, 12 and 13 are constructed to fitsnugly between the sides, lid and bottom of the case 2, and the sides,top and bottom, respectively, of the transformer 3 so that thetransformer 3 is completely encased by the assemblies 8, 9, 10, ll, 12and 13 after they are positioned in the case 2.

The use of the two-plate assemblies provides several advantageousfeatures. For instance, since the organic compounds are molded intoplates a large amount of inorganic filler substance such as silicapowder can be mixed with the organic compound without being limited byfluidity considerations of the final composition since as noted aboveexcessive amounts of silica in a mixture will reduce its fluidity. Theplate construction also permits the use of organic compounds having alow fluidity. These compounds could not otherwise be used since theirlow fluidity would prevent efficient encasement of a core-and-coilelement when the organic combination is added to a transformer case inthe form of a uniform mixture. An example of a low-fluidity organiccompound is epoxy urethane rubber. Yet another feature of thisembodiment is that it facilitates the use of organic compounds which aredifficult to set when in combination with other organic compounds. Forexample, by using separately constructed plates and unsaturatedpolyester and tung oil may be used in combination. Furthermore, in somecases the setting catalysts or promoters for two different resins havereciprocal actions on one another, such as competitive reactions, and/orhave different setting velocities thereby preventing their combined use.All of the above problems may be avoided by separately molding thecombined organic compounds in the form of plates.

The following examples are given to illustrate the manner of practicingour invention only and should not be considered or interpreted in anyway to restrict this invention. All parts given in the followingexamples are on a weight basis:

EXAMPLE I One hundred parts of unsaturated polyester resin, 20 parts ofpolyol having a hydroxyl value of 500, 20 parts of tolylene diisocyanateand 0.5 parts of a 6 percent cobalt napthenate solution were mixedtogether. Subsequent to mixing, 0.5 parts of dimethylethanol amine wereadded and mixed. To this mixture was added l part of methyl ethyl ketoneperoxide once again followed with mixing. Subsequent to mixing, 200parts of No. 6 silica sand and parts of 5 p. silica powder were alsoadded and mixed. This final mixture was placed in a ballast for two40-watt fluorescent lamps and was heated at 50 C. for 1 hour in order topromote setting.

The relationship between the d loss factor value and temperature forthis particular encasing organic combination is shown in FIG. 3. Themaximum d loss factor value resulting from the urethane ingredientappears at about 0 C. and the largest d loss factor value resulting fromthe unsaturated polyester appears at about 100 C.

EXAMPLE II Fifty parts blown asphalt were dissolved in 50 parts ofstyrene. To this mixture was added 100 parts of unsaturated polyesterresin, 1 part of a 6 percent cobalt napthenate solution and one part ofmethyl ethyl ketone peroxide. The resulting mixture was well stirred andplaced into a ballast for a 400-watt mercury lamp and was left standingat 60 C. for 1.5 hours to permit it to set. The relationship between thed loss factor value and the temperature for this particular organiccompound combination is shown in FIG. 4. It should be noted that thelargest value resulting from the blown asphalt appears at about 0 C. andthe largest d loss factor value resulting from the unsaturated polyesterappears at about 100 C.

EXAMPLE III Eighty parts of unsaturated polyester containing 40 percentby weightstyrene, 10 parts of a polyol having a hydroxyl value of 500, 9parts of tolylene diisocyanate, 1 part of benzoyl peroxide and 300 partsof silica powder ranging from to 200 mesh, were mixed together. Themixture was heated at 60 C. for 30 minutes so that it would set. Aballast for two 40-watt fluorescent lamps was charged with this mixture.The lamps were lit and noises emitted from the ballast were measured asa function of compound temperature at a 2 meter distance from theballast with a precision noise meter. The results as given in FIG. 9show effective noise reduction to levels varying from about 9 to llphons throughout the operating temperatures of the ballast correspondingto encasing organic compound combination temperatures of about 0 to 100C.

EXAMPLE IV A mixture comprising 90 parts of unsaturated polyester in a55 percent by weight styrene solution, 10 parts of blown asphalt, 2parts of methyl ethyl ketone peroxide in 60 percent by weight dimethylphthalate, 1

part of cobalt napthenate and 250 parts of calcium carbonate powder of200 mesh, was heated at 90 C. for 40 minutes so that it could set. Asequence ballast for two 40-watt fluorescent lamps was charged with themixture. The lamps were lit and noises emitted from the ballast weremeasured as a function of compound temperature at a 2 meter distancefrom the ballast with a precision noise meter. The results given in FIG.10 show effective noise reduction to levels varying from about 9 to l lphons throughout the operating temperatures of the ballast correspondingto the encasing organic compound combination temperatures of about to100 C.

EXAMPLE V mixture and noises were measured (with a precision noisemeter) as a function of compound temperature at a 2 meter distance fromthe ballast after the lamps were turned on. The results given in FIG. 11show effective noise reduction to levels varying from about 9 to about12 phons throughout the operating temperatures of the ballastcorresponding to encasing organic compound combination temperatures ofabout 0 to 100 C EXAMPLE VI Two-hundred and fifty parts of silica powder(100-250 mesh) were mixed with 100 parts of a mixture prepared by mixing75 parts of unsaturated polyester resin, 15 parts of polyether resinhaving a molecular weight of 500, 10 parts of tolylene diisocyanate, 0.1parts of dimethyl aniline and 1.5 parts of benzoyl peroxide. The mixturewas placed in a ballast for a 250-watt mercury lamp and was heated at 60C. for 30 minutes so that it would set. The lamp was lit and noisesemitted from the ballasts were measured as a function of compoundtemperature at a 2 meter distance from the ballast with a precisionnoise meter. The results given in FIG. 12 show noise reduction atslightly higher noise levels varying between and phons over theoperating temperatures of the ballast corresponding to the encasingcompound combination temperatures of about 0 to 100 C. While these noiselevels are slightly higher than the others noted, noises were reduced toa non-annoying level.

Three-hundred and fifty parts of silica powder (100-250 mesh) were mixedwith 100 parts of a mixture prepared by mixing 40 parts of unsaturatedpolyester, 50 parts of castor oil, 10 parts of tolylene diisocyanate,one part of benzoyl peroxide and one-fifteenth parts of dimethylaniline. The mixture was placed in a 40-watt sequence ballast for twofluorescent lamps and was heated at 50 C. for 60 minutes so that itwould set. The lamps were lit and noises emitted from the encasedballast were measured as a function of compound temperature at a 2 meterdistance from the ballast with a precision noise meter. The resultsgiven in FIG. 13 shows noise reduction to levels varying from about 13to 15 phons over the operating temperatures of the ballast correspondingto encasing organic compound combination temperatures of about 0 to 100C.

EXAMPLE vm Two-hundred and seventy parts of silica powder (l00-250 mesh)were mixed with 100 parts of a mixture prepared by mixing parts ofunsaturated polyester containing 55 percent by weight styrene, 5 partsof polyol having a molecular weight of 500, 5 parts of tolylenediisocyanate, 1.5 parts of benzoyl peroxide and 0.2 parts of diethylaniline. This mixture was placed into a sequence ballast for two 40-wattfluorescent lamps and was heated at 20 C. for 2 hours so that it wouldset. The lamps were lit and noises emitted from the encased ballast weremeasured as a function of compound temperature at a 2 meter distancefrom the ballast with a precision noise meter. The results given in FIG.14 show eflective noise reduction to levels varying from about 15 to 16phons over the operating temperatures of the ballast corresponding toencasing organic compound combination temperatures of about 0 to C.

EXAMPLE IX Seventy parts of unsaturated polyester, 20 parts of castoroil, 10 parts of tolylene diisocyanate, 1.5 parts of benzoyl peroxide,0.2 parts of dimethyl aniline, parts of A1 0 having an average diameterof 20 p. and 180 parts of quartz sand were mixed and subjected to atemperature of 55 C.; the mixture set. A relatively inflammable encasingmixture was produced.

EXAMPLE X Eighty-four parts of unsaturated polyester resin and 2 partsof benzoyl peroxide were added and mixed to 26 parts of a solutionprepared by mixing 12 parts of blown asphalt and 55 parts of styrene. Tothis mixture was added 250 parts of a mixture comprising calciumcarbonate and glass fibers in a 5:1 weight ratio. The resulting mixturewas placed in a ballast for two 40- watt fluorescent lamps and was leftstanding at 60 C. for 40 minutes to be set. The fluorescent lamps werelit and noises emitted from the encased ballast were measured as afunction of the compound temperature two meters from the ballast with aprecision noise meter. The results given in FIG. 15 show noise reductionto levels varying from about 14 to about 18 phons over the operatingtemperatures of the ballast corresponding to encasing organic compoundtemperatures of about 0 to 100C. 4

EXAMPLE Xl Thirty parts of a solution prepared by mixing 50 parts ofstraight asphalt and 50 parts of styrene were added and mixed to amixture containing 100 parts of unsaturated polyester resin, 0.5 partsof diethyl aniline and 2 parts of benzoyl peroxide. To this mixture wasadded parts of No. 6 silica sand and 100 parts of clay. The resultingmixture was placed in a sequence ballast for two 40-watt fluorescentlamps and heated at 60 C. for 1 hour. Subsequent to setting, thefluorescent lamps were lit and noises emitted from the ballast weremeasured as a function of compound temperature 2 meters from the ballastwith a precision noise meter. The results given in FIG. 16 showeffective noise reduction to levels varying from about 8 to 9 phons overthe operating temperatures of the ballast corresponding to EXAMPLE XIIOne hundred parts of unsaturated polyester resin containing 30 percentby weight styrene were added to 50 parts of a solution prepared bydissolving 30 parts of gilsonite in 70 parts of styrene. To this mixturewas added 200 parts of No. 6 silica sand and 150 parts of silica powderfollowed with mixing. One part of cobalt napthanate, 0.3 parts ofdimethyl aniline 0.3 parts of methyl aniline and 1.5 parts of methylethyl ketone peroxide were then added to the mixture. The final mixturewas placed in a ballast for two 40-watt fluorescent lamps and leftstanding at 50 C. for 1.5 hours to be set. The fluorescent lamps werelit and noises emitted from the ballast were measured as a function ofcompound temperature 2 meters from the ballast with a precision noisemeter. The results given in FIG. 17 show effective noise reduction tolevels of about 8 to 12 phons over the operating temperatures of theballast corresponding to encasing organic compound temperatures of aboutto 100 C.

EXAMPLE XIII Fifteen parts of a solution prepared by dissolving 40 partsof blown asphalt in 60 parts of styrene were mixed with 85 parts ofunsaturated polyester resin and 1.8 parts of benzoyl peroxide. To thismixture was added 200 parts of silica powder and 100 parts of aluminumhydroxide followed with stirring. This final mixture was placed in tensequence ballasts each ballast being for two 40-watt fluorescent lamps.The charged ballasts were left standing at 60 C. for 1 hour to be set.The lamps were lit and noises emitted from the ballast were measured asa function of compound temperature 2 meters from the ballast with aprecision noise meter. The results given in FIG. 18 show effective noisereduction varying from about 15 to 20 phons over the operatingtemperature of the ballast corresponding to encasing organic combinationtemperatures of about 0 to 100 C. In addition to determining thenoise-temperature characteristics of this particular composition, thefluorescent lamps were subjected to a source voltage 150 percent overtheir rating. Even with this voltage overload none of the organiccombinations started on fire.

COMPARATIVE TEST In order to determine the noise reduction properties ofthe combination prepared in Example XIII without any blown asphalt, 85parts of unsaturated polyester and 1.8 parts of benzoyl peroxidewereadded and mixed with parts of styrene. Also, in order to determinethe affect of hydrated aluminum hydroxide in with a precision noisemeter. The results given in FIG. 19 show only partial effective noisereduction since noise reduction at low organic compound combinationtemperatures in the 0 C. vicinity is about 27 phons.

Furthermore, when this composition was subjected to a voltage 150percent over its rating the winding or coil within the ballast burnedand broke in five out of the 10 lamps lit after only 20 minutesindicating the advantageous safety properties given an organic encasingcombination by adding a salt containing water of crystallization to theorganic combination.

EXAMPLE XIV In producing the organic combination in the form of atwo-plate assembly, the first plate of the'organic combinationresponsible for high d loss factor values at starting temperatures wasprepared by mixing 100 grams of tung oil, 20 grams of ferric chlorideand 500 grams of silica powder. This mixture was then molded into theform of a plate. The plate component responsible for providing high dloss factor values at stabilization temperatures was produced by mixing100 grams of unsaturated polyester, 1 gram of benzoyl peroxide, 5 gramsof diethyl aniline and 600 grams of silica powder and subsequentlymolding the mixture into the form of a plate.

EXAMPLE XV A plate providing high d loss factor values at startingtemperatures was molded from a mixture comprising 100 grams of castoroil, 25 grams of tolylene diisocyanate and 600 grams of silica powder.Similarly, a plate providing high d loss factor values at stabilizationtemperatures was molded from a mixture comprising 100 grams ofunsaturated polyester, one gram of methyl ethyl ketone peroxide, 1 gramof cobalt napthenate and 500 grams of silica powder. The result ing twoplates were used in combination to form the two plate assembly of thisinvention.

In conclusion it should be noted that by practicing this invention it ispossible to now effectively reduce preventing fire due to voltageoverload, 300 parts of silnoises generated by core-and-coil elements ofelectric devices, particularly discharge lamp ballasts, to non-annoyinglevels both at starting and stabilization of such electric devices.

We claim as our invention:

1. In an electric device having a core-and-coil element which generatesundesirable noises resulting from vibrational energy induced byelectromagnetic forces inherent in said device, a material disposedaround said .core-and-coil element for reducing said noises, saidmaterial comprising a physical combination of a first organic memberselected from the group consisting of polyurethane resins and a secondorganic member selected from the group consisting of unsaturatedpolyester resins.

2. The electric device of claim 1 wherein said first organic membercontains castor oil as polyol component.

3. The electric device of claim 1 wherein the first organic member has amaximum d loss factor value greater than 0.06 in the startingtemperature range of from 0 to 30 C. and the second organic member has amaximum (1 loss factor value greater than 0.06 in the stabilizedtemperature range of from to C.

combinations thereof, and the inorganic member having water ofcrystallization is selected from the group consisting of CaO- SH O, SiO8H O, BaO' 8H O, SnCl- 8H O, BaCl 2H O, CuSO; 3H O and combinationsthereof.

* l I I

1. In an electric device having a core-and-coil element which generates undesirable noises resulting from vibrational energy induced by electromagnetic forces inherent in said device, a material disposed around said core-and-coil element for reducing said noises, said material comprising a physical combination of a first organic member selected from the group consisting of polyurethane resins and a second organic member selected from the group consisting of unsaturated polyester resins.
 2. The electric device of claim 1 wherein said first organic member contains castor oil as polyol component.
 3. The electric device of claim 1 wherein the first organic member has a maximum d loss factor value greater than 0.06 in the starting temperature range of from 0* to 30* C. and the second organic Member has a maximum d loss factor value greater than 0.06 in the stabilized temperature range of from 70* to 130* C.
 4. The electric device of claim 1 which contains in addition to the first and second organic members and inorganic filler and an inorganic member containing water of crystallization.
 5. The electric device of claim 4 wherein the inorganic filler is selected from the group consisting of calcium carbonate, clay, quartz, sand, silica powder and combinations thereof, and the inorganic member having water of crystallization is selected from the group consisting of CaO. 8H2O, SiO2. 8H2O, BaO. 8H2O, SnCl2. 8H2O, BaCl2. 2H2O, CuSO4. 3H2O and combinations thereof. 